The present invention relates to an anti-condensation device for a flame sensor of a combustion chamber. The combustion in combustion chambers is controlled by means of devices which can check for the presence or absence of the flame.
If in fact the flame is extinguished, the fuel is not burnt and accumulates with the risk of dangerous unforeseen explosions.
For this reason, when the flame disappears, it is necessary to close the fuel distribution valves immediately.
The importance is therefore apparent of these devices for combustion chambers in general, and in particular for gas turbine combustion chambers.
The presence of the flame is checked by means of instruments which are sensitive to rays, such as infrared or ultraviolet rays.
The output signal of these sensors can be either of the analogue type, for example electric current intensity proportional to the flame intensity, or it can be of the digital type, which indicates simply the presence or absence of the flame.
In certain conditions of use of the combustion chamber, it is possible for condensation water to form in contact with the walls of the flame sensor. This is the result of combinations of humidity from the atmosphere, pressure and temperature of the air which assists combustion at the intake of the combustion chamber, and temperature of the surfaces of the sensor itself.
This water causes attenuation of the signal generated by the sensor, and, in extreme cases, complete disappearance of the signal which is consequently seriously to the detriment of the reliability of the control device.
The object of the present invention is thus to eliminate the above-described disadvantages and in particular to provide an anti-condensation device for a flame sensor of a combustion chamber which makes the signal reliable in all conditions of use of the combustion chamber.
Another object of the invention is to provide an anti-condensation device for a flame sensor of a combustion chamber which is particularly simple and functional, and at relatively low costs.
This object and others according to the invention are achieved by providing an anti-condensation device for a flame sensor of a combustion chamber as specified in claim 1.
Further characteristics are described in the subsequent claims.
Advantageously, the anti-condensation device for a flame sensor of a combustion chamber according to the invention can also be installed on flame sensors which are already in use.
The characteristics and advantages of an anti-condensation device for a flame sensor of a combustion chamber according to the present invention will become more apparent from the following description provided by way of non-limiting example, with reference to the attached schematic drawings, in which:
FIG. 1 is a view in cross-section of a flame sensor fitted outside the combustion chamber, according to the known art; and
FIG. 2 is a view in cross-section of a flame sensor fitted outside the combustion chamber, in which an anti-condensation device according to the present invention is used.